Characteristics of choosers (e.g., customers or users of items) can be estimated by analyzing the choice that is chosen from a set of choices by the choosers. Some information about the chooser such as a distribution of a preference vector of the chooser can be obtained from the choices of the choosers by analyzing the set of choices and the choice chosen therefrom by the chooser. The quality of the set of choices can be evaluated based on the amount of information about the characteristics obtained from the choice made by the choosers. For example, if all choices are identical, the selection from the set of choices gives no information about the characteristics of the target. Therefore, in order for more information about the characteristics of the chooser to be obtained from the choice, the set of choices needs to be properly designed.
Since the quality of a set of choices is often a black box function, it has been difficult to analytically evaluate the set of choices. In many cases, the quality of a set of choices is evaluated by a time-consuming Monte Carlo simulation. Therefore, it takes a large amount of time to find a good set of choices.